Induction of ovulation and superovulation in mares using equine LH and FSH separated by hydrophobic interaction chromatography.

This research paper investigates the application of equine luteinizing hormone (eLH) and follicle-stimulating hormone (eFSH) separated by hydrophobic interaction chromatography to stimulate ovulation and superovulation in mares, rather than using crude equine gonadotrophins (CEG), which has previously yielded unsatisfactory results.

Understanding the Problem

• Control of reproduction in mares through pharmacological means often necessitates the use of equine gonadotrophins. This is important to avert the issue of induced immunological resistance.
• The use of Crude equine gonadotrophins (CEG), which contains equine luteinizing hormone (eLH) and follicle-stimulating hormone (eFSH), has been attempted, but the outcome of superovulation experiments has been disappointing.
• Consequently, it has become necessary to separate eLH and eFSH activities from CEG to overcome this problem.

The Solution: Hydrophobic Interaction Chromatography (HIC)

• The researchers took advantage of the different hydrophobic properties of eLH and eFSH to separate them via hydrophobic interaction chromatography (HIC).
• The procedure was conducted on a phenyl Sepharose matrix to deliver separate FSH and LH fractions in good yields. The fractions were obtained by stepwise elution.
• The method was adaptable for large scale preparations of enriched fractions of eLH and eFSH.

In-vivo Experiments

• Two in-vivo experiments were conducted to assess the biological activity of the HIC fractions.
• The first experiment indicated that the LH fraction’s ovulation-inducing activity (for preovulatory follicles) was comparable to CEG, suggesting that LH bioactivity is not affect by HIC.
• The second experiment showed that the FSH fraction had the same biological activity (in terms of the ovulation rate) as CEG when it came to superovulating mares. This finding suggests that FSH activity is also not disrupted by HIC.

Conclusions

• Although the results obtained with the separate equine gonadotrophins were not better than those with CEG, the potential advantage of using preparations with single activity could be observed. The idea is to achieve a controlled balance of FSH and LH activity.
• HIC technique was chosen because it can be easily scaled up to produce large quantities of separate hormones, which is necessary for treating a large number of mares.